scholarly journals The variation with age of the structure of chromatin in three cell types from rat liver

1979 ◽  
Vol 179 (2) ◽  
pp. 291-298 ◽  
Author(s):  
V Zongza ◽  
A P Mathias
Keyword(s):  
Rat Liver ◽  
Cell Types ◽  
Repeat Length ◽  
Micrococcal Nuclease ◽  
Dna Repeat ◽  
Old Rats ◽  
Parenchymal Cells ◽  
Kinetics Of

The organization of chromatin in three rat liver nuclear populations, namely diploid stromal, diploid parenchymal, and tetraploid parenchymal nuclei, which were separated by zonal centrifugation, was studied by digestion with micrococcal nuclease and pancreatic deoxyribonuclease in 3-week-old rats in which the parenchymal cells contain diploid nuclei and in 2-and 4-month-old rats with a high proportion of tetraploid nuclei. Digestion by micrococcal nuclease allowed the estimation of DNA-repeat length in chromatin. Parenchymal nuclei have shorter repeat length than stromal nuclei and DNA-repeat length increases with the age in all three nuclei populations. The kinetics of digestion by micrococcal nuclease showed that nuclei with shorter repeat length are more sensitive to micrococcal nuclease and that the sensitivity of chromatin decreases with age for all the types of nuclei in this study. The kinetics of digestion by pancreatic deoxyribonuclease showed that sensitivity of chromatin is related to the repeat length and that the sensitivity decreases with the ages.

scholarly journals The variation with age of nuclear phosphoproteins released during micrococcal-nuclease digestion and nucleosomal phosphoproteins in three cell types from rat liver

1981 ◽  
Vol 194 (3) ◽  
pp. 963-974
Author(s):  
V Zongza ◽  
A P Mathias
Keyword(s):  
Rat Liver ◽  
Cell Types ◽  
Micrococcal Nuclease ◽  
Dna Repeat ◽  
Micrococcal Nuclease Digestion ◽  
Different Types ◽  
Nuclease Digestion ◽  
Old Rats ◽  
Parenchymal Cells ◽  
Nuclear Phosphoproteins

The nucleosomal non-histone phosphoproteins, and phosphoproteins released during the digestion of nuclei by micrococcal nuclease, were studied in three rat liver nuclear populations, namely diploid stromal, diploid parenchymal, and tetraploid parenchymal nuclei, which were separated by zonal centrifugation, in 3-week-old rats in which the parenchymal cells contain diploid nuclei and in 2- and 4-month-old rats with increasing proportions of parenchymal tetraploid nuclei. Qualitative and quantitative differences in nucleosomal phosphoprotein band patterns were found among different types of nuclei and ages. More phosphoprotein bands were found in nucleosomes derived from parenchymal than stromal nuclei. The number of phosphoproteins released during micrococcal-nuclease digestion increased with age for parenchymal nuclei. The significance of these results, considered in conjunction with the increase of DNA repeat length and decrease of nuclease accessibility with age, is discussed.

scholarly journals The distribution, induction and isoenzyme profile of glutathione S-transferase and glutathione peroxidase in isolated rat liver parenchymal, Kupffer and endothelial cells

1989 ◽  
Vol 264 (3) ◽  
pp. 737-744 ◽  
Author(s):  
P Steinberg ◽  
H Schramm ◽  
L Schladt ◽  
L W Robertson ◽  
H Thomas ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Glutathione Peroxidase ◽  
Rat Liver ◽  
Peroxidase Activity ◽  
Cell Types ◽  
Transferase Activity ◽  
Glutathione Peroxidase Activity ◽  
Glutathione S Transferase ◽  
Liver Parenchymal ◽  
Parenchymal Cells

The distribution and inducibility of cytosolic glutathione S-transferase (EC 2.5.1.18) and glutathione peroxidase (EC 1.11.1.19) activities in rat liver parenchymal, Kupffer and endothelial cells were studied. In untreated rats glutathione S-transferase activity with 1-chloro-2,4-dinitrobenzene and 4-hydroxynon-2-trans-enal as substrates was 1.7-2.2-fold higher in parenchymal cells than in Kupffer and endothelial cells, whereas total, selenium-dependent and non-selenium-dependent glutathione peroxidase activities were similar in all three cell types. Glutathione S-transferase isoenzymes in parenchymal and non-parenchymal cells isolated from untreated rats were separated by chromatofocusing in an f.p.l.c. system: all glutathione S-transferase isoenzymes observed in the sinusoidal lining cells were also detected in the parenchymal cells, whereas Kupffer and endothelial cells lacked several glutathione S-transferase isoenzymes present in parenchymal cells. At 5 days after administration of Arocolor 1254 glutathione S-transferase activity was only enhanced in parenchymal cells; furthermore, selenium-dependent glutathione peroxidase activity decreased in parenchymal and non-parenchymal cells. At 13 days after a single injection of Aroclor 1254 a strong induction of glutathione S-transferase had taken place in all three cell types, whereas selenium-dependent glutathione peroxidase activity remained unchanged (endothelial cells) or was depressed (parenchymal and Kupffer cells). Hence these results clearly establish that glutathione S-transferase and glutathione peroxidase are differentially regulated in rat liver parenchymal as well as non-parenchymal cells. The presence of glutathione peroxidase and several glutathione S-transferase isoenzymes capable of detoxifying a variety of compounds in Kupffer and endothelial cells might be crucial to protect the liver from damage by potentially hepatotoxic substances.

Chromatin from the unicellular red alga Porphyridium has a nucleosome structure

1982 ◽  
Vol 57 (1) ◽  
pp. 151-160
Author(s):  
K.L. Barnes ◽  
R.A. Craigie ◽  
P.A. Cattini ◽  
T. Cavalier-Smith
Keyword(s):  
Sodium Dodecyl ◽  
Red Alga ◽  
Repeat Length ◽  
Micrococcal Nuclease ◽  
Nucleosome Structure ◽  
Dna Repeat ◽  
Micrococcal Nuclease Digestion ◽  
Nuclease Digestion ◽  
Core Histones ◽  
Higher Eukaryotes

We have isolated a crude nuclear preparation from the unicellular red alga Porphyridium aerugineum and investigated the structure of Porphyridium chromatin. Electrophoresis of deproteinized DNA fragments produced by micrococcal nuclease digestion of Porphyridium nuclei gives a typical ladder pattern, indicative of a repeating structure. The DNA repeat-length, calculated from plots of multimer length against multimer number, varies somewhat between different digestions, ranging from 160 to 180 base-pairs (average 173). We interpret this as evidence of heterogeneity in repeat-length; the calculated repeat-length depends on the extent of digestion because chromatin sub-populations with longer repeat-lengths are on average digested earlier. Polyacrylamide/sodium dodecyl sulphate gel electrophoresis of basic proteins purified from Porphyridium nuclear preparations gives a pattern characteristic of core histones. Although our interpretation is complicated by some degradation, the result strongly suggests that Porphyridium chromatin contains each of the four core histones and that they are similar to those of higher eukaryotes. This, together with the micrococcal nuclease digestion results, demonstrates that Porphyridium chromatin is not fundamentally different from that of higher eukaryotes.

scholarly journals Immunocytochemical studies on the localization of plasma and of cellular retinol-binding proteins and of transthyretin (prealbumin) in rat liver and kidney.

1984 ◽  
Vol 98 (5) ◽  
pp. 1696-1704 ◽  
Author(s):  
M Kato ◽  
K Kato ◽  
D S Goodman
Keyword(s):  
Rat Liver ◽  
Binding Protein ◽  
Cell Types ◽  
Retinol Binding Protein ◽  
Specific Staining ◽  
Intense Staining ◽  
Cytoplasmic Staining ◽  
Liver And Kidney ◽  
Diffuse Cytoplasmic Staining ◽  
Parenchymal Cells

The immunocytochemical localization of cellular retinol-binding protein (CRBP), of plasma retinol-binding protein (RBP), and of plasma transthyretin (TTR) was studied in rat liver and kidney. The studies employed normal rats, retinol-deficient rats, and rats fed excess retinol. Antisera were prepared in rabbits against purified rat CRBP, RBP, and TTR. The primary antibodies and goat anti-rabbit IgG were purified by immunosorbent affinity chromatography, using the respective pure antigen coupled to Sepharose as the immunosorbent. This procedure effectively removed cross-reactive and heterophile antibodies, which permitted the specific staining and localization of each antigen by the unlabeled peroxidase-antiperoxidase method. CRBP was found to be localized in two cell types in the liver, the parenchymal cells and the fat-storing cells. Diffuse cytoplasmic staining for CRBP was seen in all the parenchymal cells. Much more intense staining for CRBP was seen in the fat-storing cells. The prominence of the CRBP-positive fat-storing cells changed markedly with vitamin A status. Thus, these cells were most prominent, and appeared most numerous, in liver from rats fed excess retinol. Both RBP and TTR were localized within liver parenchymal cells. The intensity of RBP staining increased markedly in retinol-deficient rat liver, consistent with previous biochemical observations. With the methods employed, specific staining for RBP or TTR was not seen in cells other than the parenchymal cells. In the kidney, all three proteins (CRBP, RBP, and TTR) were localized in the proximal convoluted tubules of the renal cortex. Staining for RBP was much more intense in normal kidney than in kidney from retinol-deficient rats. These findings reflect the fact that RBP in the tubules represents filtered and reabsorbed RBP. The pattern of specific staining for CRBP among the various tubules was very similar to that seen for RBP on adjacent, serial sections of kidney. The function of CRBP in the kidney is not known.

scholarly journals Hemoglobin and Erythrocyte Catabolism in Rat Liver: The Separate Roles of Parenchymal and Sinusoidal Cells

Blood ◽  
1972 ◽  
Vol 40 (6) ◽  
pp. 812-822 ◽  
Author(s):  
D. Montgomery Bissell ◽  
Lydia Hammaker ◽  
Rudi Schmid
Keyword(s):  
Rat Liver ◽  
Cell Types ◽  
Hepatic Cell ◽  
Sinusoidal Cells ◽  
Plasma Hemoglobin ◽  
Sinusoidal Cell ◽  
Hemoglobin Molecule ◽  
Cell Fractions ◽  
Parenchymal Cells ◽  
Stimulation Of

Abstract The liver participates in the removal from the circulation of both damaged red blood cells (RBC) and plasma hemoglobin. The specific hepatic cell types involved in these processes have been identified by fractionation of rat liver into pure isolates of parenchymal and sinusoidal cells. After injection of 59Fe-labeled hemoglobin, 85%-95% of the radioactivity in the liver was associated with the parenchymal cells, regardless of whether the hemoglobin was bound to haptoglobin or was free in plasma. By contrast, 59Fe-labeled spherocytic RBC were sequestered entirely by the sinusoidal cell population. Stimulation of microsomal heme oxygenase by administered hemoglobin or RBC indicated that these cell fractions not only sequester but also degrade the ingested hemoglobin-heme. Infusion of doubly labeled 59Fe, 125-I-hemoglobin indicated that the hepatic parenchymal cells remove the intact hemoglobin molecule without exchange or transfer of the heme moiety to other carrier proteins. By contrast, heme bound to albumin was detached from the albumin before its uptake by the parenchymal cells. These findings suggest that, contrary to previous belief, hepatic parenchymal cells play a key role in the metabolism of plasma hemoglobin.

scholarly journals Constitutive and inducible profile of glutathione S-transferase subunits in biliary epithelial cells and hepatocytes isolated from rat liver

1993 ◽  
Vol 291 (2) ◽  
pp. 641-647 ◽  
Author(s):  
M Parola ◽  
M E Biocca ◽  
G Leonarduzzi ◽  
E Albano ◽  
M U Dianzani ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Rat Liver ◽  
Cell Types ◽  
Glutathione S Transferase ◽  
Biliary Epithelial Cells ◽  
Cytosolic Glutathione ◽  
Fold Induction ◽  
Quantitative Manner ◽  
Parenchymal Cells ◽  
First Time

The constitutive and inducible cytosolic glutathione S-transferase (EC 2.5.1.18) subunit compositions of parenchymal cells (hepatocytes) and biliary epithelial cells (BEC) from rat liver have been quantitatively analysed using reverse-phase h.p.l.c. Hepatocytes, analysed in the absence of non-parenchymal cells, expressed constitutively the following subunits, in order of their concentration: 3, 4, 2, 1a, 1b, 8, 6 and 10. BEC express constitutively only four of the GST subunits expressed by hepatocytes and these are, in order of their concentration: subunits 2, 7, 4 and 3. Notable differences from hepatocytes are that BEC completely lack the Alpha-class subunits 1a and 1b that are major subunits in hepatocytes, Mu-class subunits make up a very low proportion of the total, and the Pi-class subunit 7 is a major subunit in BEC, whereas it is essentially absent from hepatocytes. For the first time, the effects of the inducing agents phenobarbitone (PB), beta-naphthoflavone (beta-NF) and ethoxyquin (EQ) have been characterized in a comprehensive and quantitative manner in both cell types. PB, beta-NF and EQ increased total GST protein in hepatocytes by approx. 2-fold, 3-fold and 4-fold respectively. Subunits significantly induced in hepatocytes were (in order of fold-induction): by PB, 1b > 8 > 3 > 2 > 4; by beta-NF, 1b > 8 > 2 > 3 > 4; and by EQ, 7 > 1b > 10 > 8 > 3 > 2 > 1a > 4. In BEC, neither PB nor beta-NF had significant effects on the total amount of GST protein, although PB did significantly induce subunit 3 at the expense of other subunits. EQ increased total GST protein nearly 5-fold in BEC, subunits 7 and 3 being induced dramatically above constitutive levels.

scholarly journals The uptake and metabolism of chylomicron-remnant lipids by rat liver parenchymal and non-parenchymal cells in vitro

1985 ◽  
Vol 232 (2) ◽  
pp. 395-401 ◽  
Author(s):  
P M Lippiello ◽  
P J Sisson ◽  
M Waite
Keyword(s):  
Endothelial Cells ◽  
Rat Liver ◽  
Kupffer Cells ◽  
Liver Cell ◽  
Cholesterol Ester ◽  
Cell Types ◽  
Chylomicron Remnant ◽  
Parenchymal Cells ◽  
Uptake And Metabolism

The uptake and metabolism of chylomicron-remnant lipids by individual liver cell types was examined by incubating remnants with monolayer cultures of hepatocytes, Kupffer cells, and endothelial cells from rat liver. Remnants were prepared in vitro from radiolabelled mesenteric-lymph chylomicra, utilizing either purified lipoprotein lipase from bovine milk, or plasma isolated from heparinized rats. The resulting particles contained [3H]phosphatidylcholine and cholesterol, and [14C]oleate in the acylglycerol, phospholipid, fatty-acid and cholesterol-ester fractions. The capacities of the three cell types for uptake of both [3H]lipids and [14C]lipids were determined to be, on a per-cell basis, in the order: Kupffer greater than hepatocytes greater than endothelial. The relative proportions of [3H]phospholipid and total [3H]cholesterol taken up by hepatocytes and non-parenchymal cells remained constant with time. The uptake of [14C]oleoyl lipids by all three cell types was slightly greater than that of the total [3H]cholesterol and [3H]phospholipid components. There was evidence of cholesterol-ester hydrolysis and turnover of [14C]oleate in the phospholipid fraction in hepatocytes and Kupffer cells, but not endothelial cells, over the first 2 h. With both remnant preparations, these observations indicate that significant differences exist between the three major liver cell types with respect to the uptake and metabolism of remnant lipid components.

scholarly journals Comparison of cadmium-metallothionein synthesis in parenchymal and non-parenchymal rat liver cells

1983 ◽  
Vol 210 (3) ◽  
pp. 769-773 ◽  
Author(s):  
K Cain ◽  
D N Skilleter
Keyword(s):  
Rat Liver ◽  
Cell Separation ◽  
Metal Uptake ◽  
Time Course ◽  
Cell Types ◽  
Separation Technique ◽  
Limiting Factor ◽  
Rat Liver Cells ◽  
A Cell ◽  
Parenchymal Cells

The time course of cadmium-metallothionein synthesis was studied in non-parenchymal and parenchymal cells, isolated by a cell-separation technique from the livers of rats after the simultaneous injection of CdCl2 (0.05 mg of Cd/kg) and a 10-fold molar excess of 2,3-dimercaptopropanol. Under these conditions of dosing, in contrast with the injection of CdCl2 alone, both cell types accumulate similar concentrations of Cd and synthesize equivalent concentrations of metallothionein. It is concluded that both cell types have a similar capacity to synthesize the metalloprotein, and that the limiting factor under normal cadmium exposure is the relatively inefficient metal uptake into the non-parenchymal cells.

Analytical Subcellular Fractionation Studies on Different Cell Types Isolated from Normal Rat Liver

1978 ◽  
Vol 55 (5) ◽  
pp. 423-427
Author(s):  
Clare Selden ◽  
A. M. Wootton ◽  
D. W. Moss ◽  
T. J. Peters
Keyword(s):  
Biliary Tract ◽  
Rat Liver ◽  
Gradient Centrifugation ◽  
Cell Types ◽  
Sucrose Density Gradient ◽  
Subcellular Fractionation ◽  
Marker Enzymes ◽  
Sucrose Density Gradient Centrifugation ◽  
Normal Rat ◽  
Parenchymal Cells

1. Parenchymal, Kupffer and biliary tract cells were isolated from normal rat liver by perfusion with collagenase solution. 2. The specific activities (munits of enzyme activity/mg of protein) of marker enzymes for the principal subcellular organelles were determined in the isolated cell homogenates and compared with whole liver homogenates. 3. The cells were disrupted and the extracts subjected to analytical subcellular fractionation by sucrose-density-gradient centrifugation. Lysosomal integrity was determined by assaying latent β-N-acetylglucosaminidase in the extracts. 4. Similar subcellular distributions were found for lysosomal, endoplasmic reticulum and plasma membrane marker enzymes in the whole liver and in parenchymal and biliary tract cells. In Kupffer cells, the proportion of these enzymes in the cytosol was significantly increased compared with the other fractions. In addition the equilibrium densities of the various organelles in these cells were lower than those from parenchymal cells.

scholarly journals Receptor-mediated endocytosis of ovalbumin by two carbohydrate-specific receptors in rat liver cells. The intracellular transport of ovalbumin to lysosomes is faster in liver endothelial cells than in parenchymal cells

1990 ◽  
Vol 270 (1) ◽  
pp. 197-203 ◽  
Author(s):  
G M Kindberg ◽  
S Magnusson ◽  
T Berg ◽  
B Smedsrød
Keyword(s):  
Endothelial Cells ◽  
Intracellular Transport ◽  
Mannose Receptor ◽  
Cell Types ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Parenchymal Cells ◽  
Rate Limiting ◽  
Kinetics Of

1. The uptake of ovalbumin (OVA) in rat liver parenchymal cells (PC) and non-parenchymal cells was studied in vivo and in vitro in order to compare the cellular expression of glycoprotein receptors and the kinetics of intracellular transport of ligand endocytosed by these receptors. 2. Ovalbumin was labelled with 125I or with 125I-tyramine-cellobiose (125I-TC). By using 125I-TC-OVA the labelled degradation products were trapped in the cells. 3. 125I-TC-OVA was rapidly cleared from blood mainly by receptor-mediated uptake in the liver. At 30 min after injection, 50% of the ligand was recovered in the liver. The endothelial cells (EC) and the PC were the predominant cell types responsible for uptake. 4. The uptake in PC was strongly inhibited by asialo-orosomucoid (AOM), but not by mannan, indicating that the uptake in these cells was mediated by the galactose receptor and not by the mannose receptor. This finding is compatible with the observation that a proportion of the OVA contains terminal galactose residues in the carbohydrate moiety. 5. In vitro uptake of OVA in cultured EC was saturable and inhibited by mannan, mannose, fructose, N-acetylglucosamine, EDTA or monensin, but not by galactose or AOM. The uptake of OVA in these cells was therefore mediated by the mannose receptor. 6. To label the organelles involved in endocytosis in PC and EC, 125I-TC-OVA was injected intravenously together with an excess of either AOM or mannan. In this way the labelled ligand could be directed selectively to EC or PC respectively. Subcellular fractionation of total liver in sucrose and Nycodenz gradients revealed that in EC the intracellular transport of OVA is so fast that endocytosed ligand accumulates and thus increases the density of the lysosomes. Conversely, in PC transfer of ligand is slower, with the result that accumulation of undegraded ligand in the lysosomes does not occur. These findings are interpreted to mean that in EC the rate-limiting step of handling of endocytosed ligand is intralysosomal degradation, whereas in PC the rate-limiting step is transport of ligand to the lysosomes. 7. Altogether, these findings suggest that endocytosis of OVA by the liver EC and PC is mediated by mannose and galactose receptors respectively, and that the kinetics of intracellular transport of OVA differ in the two cell types.

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